This application is based on the application No. 2000-5882 filed in Japan, the content of which is hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a posture detecting device that detects the posture of the object of measurement, such as the position of the body of a test subject or the orientation of an object, as well as to a breathing function measuring device that includes this posture detecting device and that measures the breathing function of a test subject.
2. Description of the Related Art
A device having a movable body of which at least the surface comprises a conductive member, a container comprising an insulating member that houses the movable body such that it is contained and freely movable therein, and multiple contact points that are located at equal intervals around the central axis of the container and in the plane perpendicular to the central axis, and at least the surfaces of which comprise conductive members, wherein where the movable body moves, two adjacent points among the multiple contact points become short-circuited, is conventionally known as a posture detecting device that detects the posture of the object of measurement (Japanese Laid-open Patent Application Sho 58-159728, Japanese Laid-open Patent application Sho 60-24410).
A posture detecting device of this type is constructed such that hen it is fitted onto the object of measurement, i.e., a test subject, or example, the movable body moves and the two points that short-circuit change as the position of the body of the test subject changes, and therefore, the posture of the object of measurement may be detected by detecting whether each contact point is short-circuited.
However, using the conventional posture detecting device described above, the two contact points that are short-circuited change from one set of two contact points to another based on the movement of the movable body that occurs when the posture of the object of measurement changes. Therefore, between a state in which given two contact points are short-circuited and another state in which two other contact points are short-circuited, there is always a situation in which the movable body is in contact with only one contact point. This situation is termed a non-sensed state in this specification. This non-sensed state is a state in which no two contact points are short-circuited.
In addition, using the conventional posture detecting device described above, when the central axis of the container is essentially vertical due to the posture of the object of measurement, the movable body stays at a position at which it is separated from all contact points, and therefore, it is not in contact with any contact points. This state is termed an open state in this specification. This open state is also a state in which no two contact points are short-circuited, as in the case of a non-sensed state described above.
Therefore, when the position of the movable body, i.e., the posture of the object of measurement, is detected by detecting the short-circuited state of the contact points, where short-circuiting is not occurring between any contact points, it is not possible to determine whether the state is a non-sensed state in which the movable body is in contact with one contact point only, or an open state in which the movable body is in contact with none of the contact points.
Furthermore, it is generally known that when a person suffers from sleep apnea, in which a relatively long episode of non-breathing occurs frequently during sleep, the arterial blood oxygen level decreases significantly or arrhythmia results. In addition, non-breathing during sleep causes the sleep to be shallow, and may cause lethargy during the day. Testing for the sleep apnea described above has conventionally used polysomnography to measure the non-breathing state, such as the number of non-breathing episodes during sleep, as well as brain waves, eye movement and oxygen saturation. In this regard, a breathing function measuring device that is capable of easily measuring the non-breathing state of the sleeping test subject without the need for hospitalization has been proposed (Japanese Laid-open Patent Application Hei 5-200031).
Using the conventional breathing function measuring device described above, because it is necessary to seek the relationship between the breathing state and the posture of the test subject, a posture detecting device is fitted onto the test subject. When this is done, the burden on the test subject must be reduced by making it easy to fit the various detecting units onto the test subject.
An object of the present invention is to provide a posture detecting device that resolve the above problems, and that, based on a simple construction, is capable of reliably detecting the posture of the object of measurement.
Another object of the present invention is to provide a breathing function measuring device that includes the above posture detecting device and that reduces the burden on the test subject by making the fitting of the device to the test subject easy.
In order to attain these objects, the posture detecting device pertaining to the present invention comprises: a first movable body of which the surface comprise conductive member; a first container for housing the first movable body, such that it is contained and freely movable therein, and for having a first multiple contact points of which the surfaces comprise conductive members; a second movable body of which the surface comprise conductive member; and a second container for housing the second movable body, such that it is contained and freely movable therein, and for having a second multiple contact points of which the surfaces comprise conductive members, herein the first and second containers are positioned such that when the two adjacent contact points of the first container are not short-circuited by the first movable body, two adjacent contact points of the second container are short-circuited by the second movable body.
In order to attain the above objects, the breathing function measuring device pertaining to the present invention comprises: a wrapping member for wrapping around the chest or the abdomen of the object of measurement; a change amount detecting unit, which is located at one end of the wrapping member, for detecting the amount of change in the circumferential length of the chest or the abdomen due to the breathing effort of the object; and a posture detector, which is located inside the change amount detecting unit, for detecting the posture of the object.